Currently known minimally invasive procedures for diagnosis and treatment of medical conditions use shapeable instruments, such as steerable devices, flexible catheters or more rigid arms or shafts, to approach and address various tissue structures within the body. For various reasons, it is highly valuable to be able to determine the 3-dimensional spatial position of portions of such shapeable instruments relative to other structures, such as the operating table, other instruments, or pertinent anatomical tissue structures. Such information can be used for a variety of reasons, including, but not limited to: improve device control; to improve mapping of the region; to adapt control system parameters (whether kinematic and/or solid mechanic parameters); to estimate, plan and/or control reaction forces of the device upon the anatomy; and/or to even monitor the system characteristics for determination of mechanical problems. Alternatively, or in combination, shape information can be useful to simply visualize the tool with respect to the anatomy or other regions whether real or virtual.
However, a primary difficulty in using flexible devices is the inability to determine the location and/or shape of the flexible device within the body. In non-flexible, discrete devices, such detection and monitoring tasks may be accomplished with encoders or other techniques (such as visual tracking of a portion of the device external to the body) that utilized the rigid nature of linkages. Such conventional techniques are not practical with flexible device as such devices contain non-rigid linkages or too many individual linkages to effectively determine location and/or shape of the flexible device.
There remains a need to apply the information gained by the localization techniques to determine the location, orientation and shape of a flexible device and applying this information to produce improved device control or improved modeling when directing a robotic or similar device. There also remains a need to apply such controls to medical procedures and equipment.